It is currently called the Diocese of Lamezia Terme, and it is a suffragan of the Archdiocese of Catanzaro-Squillace.

[3][4] The earliest appearance of the name Nicastro is in the Diatyposis (Νέα Τακτικά) of Leo the Wise, composed at Constantinople around 900.

The church in the village below the citadel of Nicastro was built and endowed by the Norman Aumberga, the niece of Robert Guiscard and sister of Count Richard Dapifer, the son of Drago.

The Capuchins established the convent of S. Maria degli Angeli in 1545; provincial chapters of the Order met there in 1550, 1556 and 1618.

In 1985, following the signing of a revised concordat with the Italian Republic, the Vatican Secretary of State issued a set of instructions (Normae) for implementing some of its provisions, "so that the names [of dioceses] might be more appropriately accommodated to new circumstances, and better respond to the current necessities of civil and social life.

"[17] On 27 September 1986, after appropriate consultations, Pope John Paul II granted permission to the Congregation of Bishops to implement the norms.

In the case of Nicastro, the Congregation issued a decree on 30 September 1986, in which the long-standing name of "Neocastrenses" was retained for business of the Curia (i.e. for ecclesiastical matters), but in the vernacular it was to be referred to as "Diocesi di Lamezia Terme".